Tubing string sand trap



July 15, 1958 w. s. CRAKE TUBING STRING SAND TRAP Filed Jan. 7, 1954 FHGURE 3 HeuzE 1 FIGURE 4 \nven+or: E W5. CEAKE L5 H14 6 His A qen+ FIGURE United States PatentOfiice 2,843,054 Patented July 15, 1958 opment Company, New York, N. Y., a corporation of Delaware Application January 7, 1954, Serial No. 402,618

3 Claims. (Cl. 103-220) This invention relates to well production equipment and pertains more particularly to apparatus adapted to prevent or minimize the settling of sand within a tubing string which is employed in a well to reciprocate a well pump.

In some oil fields, varying quantities of sand are pumped to the surface along with the oil. Frequently, a well prime mover which reciprocates the pump may stop due to breakdown of some part of the equipment. In other instances, the well prime mover may be automatically or manually stopped periodically on a set time schedule when the well is being produced by. intermittent pumping. For example, in, wells where the capacity of the pump is greater than the amount of oil flowing from the oil-bearing formation into the well borehole, the well pumping installation may be shut off for predetermined periods, say, twelve hours out of every day.

When the well pumping installation is stopped, the sand carried in suspension by the column of oil in the production or tubing string settles to the bottom of the well and piles upon the top of the pump plunger and clogs the valves. This causes sanding up of the pump which often requires the removal of the pump plunger for repairs. This sanding up of oil well pumps occurs in wells where the pump is reciprocated by a conventional sucker rod string, or where the pump is actuated by the reciprocation of the production or tubing string, as shown in U. S. Patent No. 2,552,153, issued May 8, 1951, to W. S. Crake. 7

Apparatus to prevent sanding up of wells having pumps operated by sucker rod string is disclosed in my copending patent application, Serial No. 289,813, filed May 24, 1952 now U. S. Patent No. 2,669,940. It is the primary object of the present invention to provide relatively simple and inexpensive sand trapping apparatus adapted to be positioned in an oil production tubing string used to actuate a reciprocating well pump for preventing sand from settling on the pump when the pump is not operating. 9

Another object of this invention is to provide sandcatching apparatus which may be easily installed in a tubing string used to reciprocate a plunger-type pump within a well borehole for catching sand at different levels as it settles out of the column of oil above the pump when the pump is not operating.

A further object of this invention is to provide simple and effective sand-trapping apparatus adapted to be secured in a production tubing string above a reciprocating well pump for efiectively closing the production tubing at varying levels when the pump is not operating, said sand-trapping apparatus at the same time being adapted to open the tubing string and allow oil to be produced therethrough when the pump is operating.

Another object of the present invention is to provide a sand-trapping device adapted to be mounted in a well production tubing to form a substantially horizontal 2 barrier within the production tubing upon which sand may settle when the well is not pumping.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

Figure l is a longitudinal view of a Well pump positioned in a well borehole and reciprocated by a tubing string having a plurality of sand-trapping devices mounted therein.

Figure 2 is a longitudinal view, partly in cross-section, of the present sand-trapping apparatus mounted within a section of production or tubing string above a reciprocating well pump.

Figures 3 and 4 are diagrammatic views of the present sand-trapping apparatus during various phases of well production operations.

Referring to Figure 1 of the drawing, a reciprocating type pump 11 is shown as being positioned in a borehole 12 which is lined in a conventional manner with well casing 13. A slip assembly 14 is provided above the pump 11 to anchor the pump securely in the bottom of the well casing 13.

The piston within the oil well pump 11 is reciprocated by a tubing string 15 which is made up of a plurality of sections of tubing to a length sufficient to extend to the top of the borehole where it is secured to suitable prime mover means, not shown.

Fixedly secured within the tubing string 15 above the pump 11 are one or more sand-trapping barriers 16 which are made of a flexible material such as rubber, synthetic rubber, rubberized canvas or various plastic materials. Preferably, an oil-resistant material is employed thus reducing the rate at which the barriers deteriorate and become worn out.

Each sand-trapping barrier 16 is a substantially fiat flexible disc having a plurality of perforations 17 such as holes'or slots therethrough, said perforations being of a size not much greater than the size of the sand particles being pumped when the barrier 16 is in its unflexed position. Thus, the sand-trapping barrier 16 is actually a perforated rubber diaphragm which is preferably molded with a metallical ring 18 in its peripheral edge. The metallic ring 18 prevents deformation of the diaphragm 16 while it is being assembled into the tubing string 15.

While the perforated diaphragms or sand-trapping barriers 16 may be mounted in the tool joint between the threaded ends of any two sections of tubing string 15, as shown in Figure 4, each perforated diaphragm 16 is preferably mounted in a separate tubular housing 202tla for ease of assembly between any two sections of the tubing string 15 as shown in Figure 2. Thus, the beaded edge of the perforated diaphragm 16, which is slightly larger in diameter than the bore 21 of the housing 20-20a, rests on a shoulder 22 formed on the lower part of the housing 20a and is secured in place by screwing down the upper part of the housing 20 as tightly as possible. The upper and lower portions of the housing 2tl-2tla are threaded as at 23 and 24, respectively, for connection to adjacent sections of tubing string 15 as shown in Figure 2.

The thickness of the perforated diaphragm 16 is determined by the strength of the materials used and the diameter of the tubing string 15 in which the diaphragm is to be positioned, the thickness being suflicient to support a substantial quantity of sand which settles on the dia phragm in its unflexed position, as shown in Figure 4.

In operation, when the pumping installation illustrated in Figure 1 is shut down, the tubing string 15 is not reciprocating, and the sand-trapping diaphragm 16 remains stationary, as shown in Figure 4, in substantially a horizontal position. Any sand that was being carried by the production fluid up the tubing string 15 during pumping operations, settles in a pile 25 on top of the perforated diaphragm 16 as shown in Figure 4. The same settling action takes place at disc or diaphragm 16 which is secured within the tubing string 15 with the sand carried by the well fluid between'any two diaphragms settling out on the lower diaphragm.

As shown in Figure 3 of the drawing, when the well is being pumped, well fluid is forced up the tubing string 15 so that each of the sand-trapping diaphragms 16 is flexed upwardly as shown in Figure 3. Flexing of the diaphragms 16 causes the perforations 17 therein to open and become larger thus allowing the passage therethrough of the well fluid including the sand carried thereby. The restriction to the fluid flow in the tubing string 15 is merely that head required to flex the diaphragms or discs 16 so that the holes therein are open to permit passage of fluid. Any sand that has collected on the top of the diaphragm will be readily loosened therefrom when the diaphragm 16 is flexed the first time after a pump has started. The flow of fluid through the perforated diaphragms continues to disperse any sand in the tubing string 15 above each diaphragm and pump it upwardly through the tubing string 15 and out of the well. The number of sand-trapping diaphragms 16 employed depends on various factors, such as the depth of the well and the amount of sand pumped by the well pump. At least one of the perforated diaphragms is positioned immediately above the-pump while others are placed at suitable intervals along the tubing string 15.

I claim as my invention:

1. In a well pumping installation comprising a reciprocating-piston-type well pump positioned in the lower end of a Well, the combination of a production tubing string suspended within said Well substantially throughout the length thereof for reciprocation therein, the lower end of said tubing string being affixed to the pump piston for reciprocating said pump piston in a substantially vertical plane, and sand-trapping means within said tubing string above said well pump for catching sand settling in the tubing when the pump piston is not reciprocating, said sandtrapping means comprising substantially flat flexible disc means having perforations therethrough and extending transversely in said tubing with the peripheral edges of said disc means secured to said tubing string.

2. In the well pumping installation comprising a reciprocating-piston-type well pump positioned in the lower end of a well, the combination of a production tubing string suspended within said well substantially throughout the length thereof for reciprocation therein, the lower end of said tubing string being affixcd to the pump piston for reciprocating said pump piston in a substantially vertical plane, and sand-trapping means within said tubing string above said Well pump for catching sand settling in the tubing when the pump piston is not reciprocating, said sand-trapping means comprising substantially flat flexible disc means having perforations therethrough, and stiffening means carried by the peripheral edges of said disc means, said disc means extending transversely in said tubing with the stiflened peripheral edges of said disc means secured to said tubing string.

3. In a well pumping installation comprising a reciprocating-piston type well pump positioned in the lower end of a well, the combination of a production tubing string suspended within said well substantially throughout the length thereof for reciprocation therein, the lower end of said tubing string being aflixed to the pump piston for reciprocating said pump piston in a substantially vertical plane, and a plurality of substantially flat disc-shaped elements mounted in the tubing string transversely thereto and in spaced relationship from each other, said discshaped elements being provided with a plurality of perforations, the diameter of said disc elements being slightly in excess of said tubing string, and means for fixedly securing the rim of each disc element to the inner wall of said tubing string, whereby the central area of said disc elements may be flexed upwardly and downwardly opening said perforations during normal pumping operations to allow the well fluid to pass therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 270,853 Sinclair Jan. 16, 1883 582,561 Turner et a1 May 11, 1897 603,941 Cartwright May 10, 1898 670,794 Lott Mar. 26, 1901 851,388 Wallace Apr. 23, 1907 996,588 Kennedy June 27, 1911 1,428,399 Schilling Sept. 5, 1922 2,138,002 Hall Nov. 29, 1938 2,194,154 Scott Mar. 19, 1940 2,332,114 Robb Oct. 19, 1943 2,465,404 Sonntag Feb. 20, 1947 2,659,442 Sutliflf Nov. 17, 1953 2,674,318 Sutlifr Apr. 6, 1954 

